Isolation and Identification of F Lavonol Glycosides from Lathyrus armenus (Boiss. & Huet)

In the last five decades study on plant secondary metabolites have been increasing. Higher plants with a wide range of secondary metabolites have been very important in the search of new therapeutic agents. In this study secondary metabolites of Lathyrus armenus (Boiss. & Huet) which are endemic in Turkey, were studied. Flavonol glycosides (Rhamnocitrin-3-O-rhamninoside, Rhamnetin-3-O-rhamninoside, Rhamnazin- 3-O-rhamninoside, kaempferol3-O-rhamninoside and, kaempferol-3-O-glucosyl (1→2) rhamnoside) were isolated by different chromatographic methods and identified by 1H, 13C NMR, as well as 2D NMR and Mass spectroscopy techniques from ethyl acetate and aqueous fractions of L. armenus’s methanolic extract. This is the first study about secondary metabolites of Turkish Lathyrus species.


Introduction
The family of Leguminosae is one of the largest plant family with 750 genera and more than 18,000 species (1). Leguminosae is divided into three subfamilies namely Papilionoideae, Mimosoideae, and Caesalpinieae. Papilionoideae, and the largest subfamily of Leguminosae which contains 476 genera and 13,860 species is also the most diverse and widely distributed. Includes most of the familiar domesticated food and forage crops and model genetic/genomic species (2). Lathyrus (Leguminosae; Papilionoideae) is the largest genus in tribe Fabeae and exhibits an extensive distribution (3). The genus Lathyrus L. is divided into three subfamilies and 36 tribes and about 19,325 species of annual and perennial plants (4,5), which are mainly distributed throughout the Northern Hemisphere, like seasonally dry Mediterranean basin and neighboring western Irano-Turanian region. North America and temperate areas of South America are the second regions of diversity and a few species are grown in tropical East Africa. Most members of Lathyrus habitant are open woodlands, forest margins, and roadside verges, but littoral, alpine and more drought-tolerant species are also existent (3). In the Flora of Turkey, placed 58 Turkish species (6).
L. armenus is one of endemic species of Turkey. This species is growing in Erzrum, Sivas, Gumushane and Van. In this study the isolation and identification of flavonoits from the whole plants of L. armenus (which collected from Sivas) were investigated, and the constituents were isolated and identified based on the spectral data.

General
Methanol, n-hexane, CHCl 3 , EtOAC were purchased from Sigma-Aldrich. Silica gel 60 (0.063-0.200 mm), acetonitril and RPmodified Silica Plates were purchased from Merck. The ACE 5, C18 250×4.6 mm, and ACE 10, 250×10 mm HPLC column was used for analysis. Varian Mercury 400MHz Nuclear Magnetic Resonance was used for NMR spectroscopy and Agilent 1100 HPLC series was used for HPLC analysis.
Plant material and isolation process L. armenus was collected from Sivas, Turkey, during the flowering period. Voucher species were identified and the plant sample was deposited for future reference in Ankara University, Faculty of Pharmacy (AEF: 26680).
The dried and powdered aerial parts of L. armenus (800 g) were extracted with methanol by Soxhlet extraction for 12 h. The residue was evaporated under the vacuum and dried (156.185 g) and then partitioned successively between H 2 O and n-hexane (47.238 g), CHCl 3 (1.440 g), EtOAC (5.810 g), the residue or water fraction (97.129 g).

Discussion
The Lathyrus genus plants have endemic importance due to their usage as a food, fodder and ornamental crops. This species of plants contains approximately 25% of protein, and they are similar to other commonly used grain legumes, such as peas and fava beans. However, nonprotein amino acid (β-N-oxalyl-l-α, β-diaminopropionic acid (β-ODAP)) also is found in Lathyrus species in low concentration. Literature data have demonstrated that Lathyrus species contain functional compounds including phenolics with antioxidant activity.
Further studies on L. cicera released that seeds contain 37 glycosylated flavonoids which were identified by HPLC-DAD-ESI/ MS method. Kaempferol glycosides were detected as the main glycosides and quercetin, isorhamnetin, apigenin as well as luteolin glycosides were also determined (14).
L. digitatus aerial parts content of phenolic acids and flavonoids were determined. Most of the flavonoids were identified as kaempferol and quercetin derivatives according to their mass fragmentations (15).
Flavonoids are omnipresent in higher plants, and improve plant-microbe interactions, plantanimal interactions. Flavonoids prevalence in plants make them important components in the control of inflammation and cancer prevention (16). Flavonoids are the most widely distributed secondary natural metabolites ,found in the plants occuring in free forms or as glycosides with polyphenolic structure. Becouse of the biochemical and antioxidant properties of flavonoids, these classes of secondary metabolites are associated with wide rang of health-promoting effects such as NF-K B activation, aldose reductase inhibition, insulin receptor activator, anti-carcinogenic, anti-mutagenic , etc. There are so many invivo and in-vitro studies about usefulness of flavonoids. They are using as nutraceutical, pharmaceutical, medicinal, and cosmetical pupose. (17,18,19). Kaempferol and quercetin and their glycosides were present in 36 of 38 Lathyrus species. According to the litrature survey Flavonoids with 3-sophoroside-7glucoside, 3-robinobioside 3-sophoroside and the 3-lathyroside-7-rhamnoside moiety were isolated from this genus. of Cicer, Lens, Pisum and Vicia indicate that each genus has a distinctive flavonoid profile (8).